1. Field of the Invention
The present invention relates to a method for testing a non-volatile memory, and more particularly, to a method for testing whether the non-volatile memory is written with a code assigned by the client or not.
2. Description of the Prior Art
To verify the validity of a non-volatile memory (such as a flash memory or an electrically erasable programmable ROM (EEPROM)), a series of testing procedures are performed before the non-volatile memory leaves the factory.
FIG. 1 depicts a flow chart of the conventional method for testing a non-volatile memory. In step 101, it depicts the beginning of the flow chart of the conventional testing method. In step 102, an open/short test of the pins of the non-volatile memory is executed, if it is affirmative, step 103 is proceeded; otherwise, step 106 is proceeded and the memory is binned to binning category 2. In step 103, a functional test of the non-volatile memory is executed, if it is affirmative, step 104 is proceeded; otherwise, step 106 is proceeded with and the memory is binned to binning category 3. In step 104, an erasable and programmable test of the non-volatile memory is executed to determine whether the data of the non-volatile memory can be erased and new data can be rewritten in the memory or not, if it is affirmative, step 105 is proceeded; otherwise, step 106 is proceeded and the memory is binned to binning category 4. In step 105, a code test of the non-volatile memory is executed. In the code test, the code written in the non-volatile memory is read out and compared it with the original code. If the result is identical, step 106 is proceeded and the memory is binned to binning category 1; otherwise the memory is binned to binning category 5. All memory will be binned in step 106. In step 107, the flow chart of the conventional testing method ends.
In other words, the opening/shorting of the pins, logic function, erasable function and reading writing function of the memory can be checked in the conventional method, but it cannot be checked whether the code written in the memory is assigned by the client or not. For example, if the controlling program of the testing machine retrieves a code which is not assigned by the client, the result of the read write function test will affirmative, since the read write function test of the memory is to read out the code written in the memory and compare it with the code retrieved by the controlling program of the testing machine.
In accordance with the problem of prior art, the present invention discloses a method that can not only test the short/open of the pins, logic function, erasable function and read write function of the memory but also test whether the code written in the memory is assigned by the client or not.